1. Field of the Invention
The present invention relates to a communication method over a Bluetooth™ network, and more particularly to a Bluetooth network communication method for implementing radio communication in accordance with a quality required for different kinds of communication services.
2. Description of the Related Art
Bluetooth is a standard wireless technology for connecting digital devices such as mobile telephones, mobile computers and digital, electric home appliances in a radio manner in order to exchange data including images and voices. The area available for the connection through the Bluetooth is the order of 10 meters radius, which is less than the connection distance of the conventional radio LAN. However, it can be achieved with a lower cost and an easier configuration. Further, since its low power consumption leads expectations to be used as a communication medium between digital devices within a local area network.
In a Bluetooth network, one or a plurality of Bluetooth devices, each of which is called “slave”, are connected in the radio manner to one Bluetooth device called “master”. Here, each of the Bluetooth devices includes a radio interface compliant with the Bluetooth Standard. Each slave can perform different kinds of radio-communications with the master.
For example, in an example shown in FIG. 1, a personal computer (PC) (called master 1 hereinafter) compliant with the Bluetooth Standard is used as a master, to which multiple devices are connected in the radio manner. A headset 2, which is one of the slaves, performs voice communication through Synchronous Connection-Oriented (SCO) that is a form of connection suitable for voice transmission in real time. On the other hand, a mouse 3, which is a PC peripheral device, also has a Bluetooth interface and transmits sequential signals to the master 1 in the radio manner in asynchronous with clock signals. The communication in this case is performed in a form of connection called Asynchronous Connection-less (ACL). Further, a viewer 4 transmits image data to the master 1 in the radio manner.
FIG. 15 shows a protocol layer configuration in a conventional Bluetooth network. In a lowest RF (radio) layer 101, regulations required for antenna control and/or radio transmission are defined. A baseband 102 is a physical layer and handles regulations for managing physical channels and links. Further, the configuration includes an a Logical Link Control Adaptation Protocol (L2CAP) 103 via a Host Controller Interface (HCI).
The L2CAP layer 103 further regulates ACL data services to protocols in upper layers and sets a logical channel for each service. As Quality of Service (QoS) options, QoS parameters including the token rate, token packet size, peak bandwidth, latency and delay variation can be defined for each logical channel. Further, a primitive called HCI_QoS_Setup is prepared for the HCI, and the same QoS parameters as the above can be defined for each connection handle.
According to the conventional system shown in FIG. 15, a channel is set in accordance with a given type of quality of service in the L2CAP level. However, one connection handle for the ACL link is used by the protocol in the L2CAP layer 103 for one Bluetooth interface. More precisely, there is only one connection handle for the ACL link for the Bluetooth interface for a pair of a sender and a receiver (for example, one slave and one master shown in FIG. 2).
The connection handle is like an identifier for identifying a connection link. In the example in FIG. 15, only one connection handle A is commonly used for all of communication services requiring data when the pair of the slave and the master exchanges asynchronous signals via the ACL link.
Therefore, logical channels specified in the upper L2CAP layer 103 for a plurality of types of communication services (that is, for respective QoS), respectively, performed between one slave and the master are bundled in the single connection handle A in the lower baseband layer 102. Thus, processing corresponding to the communication quality required by each logical channel cannot be performed.
Furthermore, there is a single buffer 104a only, corresponding to one ACL link, in order to accommodate packets via (or utilizing) the ACL link. Thus, even when different communication quality is required by the upper level layer, the same quality of communication service is provided to all packets via (or utilizing) the ACL link.
For example, when a viewer shown in FIG. 2 requires two services of video transmission and keyboard operation (or mouse operation) via the ACL link, communication services, one of which handles the continuity of images and the other of which achieves faster responses, are required for the video transmission and the keyboard operation, respectively. In the L2CAP, logical channels corresponding to these two services are defined, and channel ID's are given, respectively. However, the communication processing is performed through the same quality of services as a result. Thus, the video requiring the continuity may be played intermittently, or, conversely, a command operation requiring a quick response may be delayed.
In this way, in the conventional Bluetooth network communication, communication reflecting the QoS parameter for each logical channel is not performed.